When implementing your lookup_order MCP tool, the backend sometimes returns errors (e.g., “Order not found”…

Question

When implementing your lookup_order MCP tool, the backend sometimes returns errors (e.g., “Order not found” or temporary database failures). What is the correct pattern for communicating these errors back to the agent?

Accepted Answer

B. Return the error message in the tool result content with the isError flag set to true

Answer

A. Throw an exception from the tool handler so the agent framework can catch and log it

Answer

C. Log the error server-side and return an empty result to avoid confusing the model

Answer

D. Return a success response with a “status” field indicating the error type

Question 33